Fixes: #9821
Issue link: https://github.com/spring-projects/spring-integration/issues/9821
Previously, Spring Integration used JSch library for SFTP protocol,
and that one was able to follow symlinks.
Currently, the `SftpSession` uses `LSTAT` command which does not follow symlinks
* Fix `SftpSession` to call `sftpClient.stat()` instead of `lstat()`
to mitigate migration pain from JSch
(cherry picked from commit efa8dc50b7)